1. Field of the Invention
The present invention relates to optical communications assemblies, and particularly to a multi-fiber array assembly.
2. Description of Prior Art
Fiberoptics has been the driving force in the current communication revolution which has enabled carriers to achieve enormous data throughput. In order to realize the full potential of fiber optics, the technology is being incorporated into all facets of integrated electronics. This makes it possible to fully utilize the enormous bandwidth of the optical fiber in conjunction with the high speeds of semiconductor integrated circuitry.
Therefore, arrays of optical fibers need to be coupled precisely and reliably to semiconductor laser and detector arrays on an integrated circuit chip. Already, various groups throughout the world have demonstrated the feasibility of high-speed optoelectronic VLSI switching and two dimensional fiberoptic arrays for an optical crossbar switch. Such devices are disclosed in, for example, High-Speed Optoelectronic VLSI Switching Chip With greater than 4000 Optical I/O Based on Flip-Chip Bonding of MQW Modulators and Detectors to Silicon CMOS, Anthony L. Lentine et al., Vol. 2, No. 1, p. 77, April 1996, and Fabrication of Two-Dimensional Fiber Optic Arrays for an Optical Cross-Bar Swith, Geoff M. Proudley, Henry White, Optical Engineering, Vol. 33, No. 2, pp. 627-635, February 1994.
The above publications purport to achieve a fiber array positional accuracy (center-to-center spacing error) of approximately +/xe2x88x925 micrometers. However, such accuracy cannot meet the need of present day optoelectronic devices such as charge couple devices (CCDs), photodetectors and lasers using semiconductor technology. A high precision fiber arrays with center-to-center spacing errors not exceeding +/xe2x88x922 micrometers is needed to meet current requirement.
U.S. Pat. No. 5,907,650 disclosed a high precision fiber array assembly having center-to-center spacing error not exceeding +/xe2x88x922 micrometers. Referring to FIG. 1, the array disclosed an optical fiber 1 comprising a central core 2, a cladding layer 3 and an outer jacket 4. One end of the fiber 1 is stripped to expose an end having a predetermined length. Thereafter, the exposed end is shaped to form a conical tip 6.
Referring also to FIG. 2, fiber receiving openings 7 are formed in a mask 8. This is preferably done by laser machining from a rear side (fiber insertion side) of the mask 8. The openings 7 are formed in a suitable predetermined pattern with predetermined spacing.
Referring also to FIG. 3, to assemble the array, the tip 6 of the fiber 1 is inserted into a corresponding receiving opening 7 from the rear side of the mask 8. A periphery of the tip 6 engages the mask 8 at a rearmost portion of the corresponding receiving opening 7. After all fibers 1 are completely inserted into the openings 7, bonding material 9 is applied to a front side of the mask 8. The bonding material 9 covers the tips 6 and fills the openings 7, and covers the front side of the mask 8. Thereafter, the tips 6 and bonding material 9 are ground and polished. This removes a portion of the bonding material 9, and removes portions of the tips 6 such that front faces of the cores 2 are exposed.
Because the fibers 1 are secured in the openings 7 of the mask 8 with the bonding material 9, assembly of the array is irreversible. If any fiber is found to be damaged or malfunctioning, it is almost impossible to repair or replace. The entire array must be discarded, and replaced with a new one. The cost of each array is relatively high. Thus, an improvement multi-fiber array overcomes the abovementioned problems is desired.
Accordingly, an object of the present invention is to provide a design which can be disassembled to replace and repair any damaged element
Another object of the present invention is to provide a design which has a low assembly costs.
To achieve the above objects, a multi-fiber array assembly in accordance with the present invention comprises a main housing, a ferrule holder, a stopper, a front plate, a strain relief assembly, a plurality of springs and a plurality of ferrules with optical fibers retained therein. The ferrule holder is retained in the main housing, and comprises a ferrule holding plate defining a first array of holes therethrough. The stopper is secured to the ferrule holder at a location rearwardly of the first array of holes, and defines a plurality of passages therein. Each ferrule has a conical front end and is extended in a corresponding hole of the first array of holes. The springs are compressed between the ferrules and the stopper thereby exerting a forward pushing force to the ferrules. The optical fibers extend through the passages of the stopper. The front plate is secured to a front end of the ferrule holder and defines a second array of the holes therein. Each holes of the second array has a rear conical section in which the conical front end of a corresponding ferrule is fitted. The strain relief assembly is secured to a rear end of the main housing, and a water-proof rubber block is mounted between the main housing and the strain relief assembly to provide a watertight seal therebetween. The waterproof rubber block defines a third array of holes corresponding to the first and second arrays of holes. The optical fibers extend through the third array of holes, respectively, and are held in the water-proof rubber block so as to be watertight.